Can't tell if you're pulling my leg or just trolling %^)
The original author of this thread made a claim that there was a underground (or underwater) explosion that pushed stuff straight up. The same author claimed that the dark circular spot immediately NE of the two ships was the evidence for the outlet for some sort of maniacally directed charge from (I think) the main charge at the storage facility, facilitated by some kind of tunnel or cavern under the sea.
That's bollocks.
If those ships were atop a hole from which an explosion erupted, this explosion as the poster claimed, they'd be somewhere else right now, folded in half... Never mind jet skis.
If you're claiming that the ships were just jostled due to the obvious blast from the storage facility, then I retract the "troll" comment %^) Have no issues with that, since it's in agreement with my assertion. Look at the apparent damage on deck of those two ships - the stern-end decks are looking mildly dirty or scorched, compared to the rest of the decks. And here, that dark spot is pretty much directly under the ships, but I think that's more now that the harbor water there is in the ship's lees, so the darker area is currently due to the lack of wind (out of the SW) at the surface.
Check out the brand new image on Google Earth - it was updated as of 04 August - that's amazingly fast, but very cool and for such an obviously notable event. And the older shot is from a slightly different azimuth, but only two months older.
AFTER:
Then "push the button, Max"
BEFORE:
Where the storage structure was you can see beach below, it certainly isn't very deep there. Sure, you could claim that the sand all slid into the former opening to the secret passage, but that's for a later post.
The devastation was extreme in the x-y (horizontal) direction. Nearly a circle half a km in all directions (except where that concrete"silo" structure was an effective block). Yet, notice that a "block" back from the shoreline there are low containers and things more or less still standing, though some of them are definitely crescent-shaped now... The propagation of the shock wave right along the surface is impeded greatly by obstacles, and quickly devolves into turbulent flow, reducing its force and speed. In fact, while it's not subject to some debate, if you measure the height vs width of the vapor/shock cloud in my last post, the horizontal radius is about 10-15% less than the vertical, suggesting the above.
Now, on to something completely different:
Note the storage structure is about as long as the silo to the WSW. And again, I have no information on how the ammonium nitrate was distributed throughout the facility, but that building was about 130 m x 40 m, or 5200 sq m in area. The material is about 1.7x the density of water, but since it's packed in bags, and not all that evenly, maybe 1.3x average? Why not. So ~2750 tonnes (thanks,
@Keith Beachy, I'll assume you're thinking metric) means about 2100 cu m, doesn't even fill the building to 1/2 m deep. And since we saw a picture of it stacked up at least as high as the ex-people playing with fireworks right in front of the pile, it may have been concentrated into a pile 2 m high by 1050 sq m in footprint. If rectangular, more or less in the ratio of the building, the charge would have roughly been 35 m x 10 m x 2 m in size. Of course, this is a WAG, and I have no idea the real shape of the material. But, compared to the building this is more like a point charge, so very quickly the propagating wave would look more or less circular on the ground, with divots carved out where there were sturdy obstacles. Vertically, it'd be quite uniform.
The wave propagated toward the silo building, gouging out the center (but interestingly, not penetrating through), it appears like a fairly uniform diffraction around the N/S ends of the silo, as the destruction to the west of the silo is fairly uniform as well. (Except for that one little structure square west of the silo, right at the center!)
I don't know the height of the dock area vs the water at that time of day, but those two ships being in close and the shock not coupling well to the water right at the dockline would cause a lot of the shock wave to potentially pass over much of the ships' decks, and not get down onto the hulls, with way more cross-section. Ground clutter really makes a difference to a surface explosion.
Ok, enough armchair analysis. Time to get a life!
Cheers - Jon N7UV